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// RUN: %target-swift-frontend -disable-availability-checking %s -emit-sil -o /dev/null -verify
// REQUIRES: concurrency
// Tests for the use of 'rethrows' on generic functions that have AsyncSequence
// and AsyncIteratorProtocol requirements.
func f1(_ seq: some AsyncSequence) async rethrows {
for try await _ in seq { }
}
func f2(_ seq: some AsyncSequence, body: () throws -> Void) async rethrows {
for try await _ in seq {
try body()
}
}
func f3(_ seq: some AsyncSequence, _ seq2: some AsyncSequence) async rethrows {
for try await _ in seq {
}
for try await _ in seq2 {
}
}
enum HomeworkError: Error {
case dogAteIt
}
func testCalls(x: some AsyncSequence<Int, Never>, y: any AsyncSequence<Int, any Error>) async throws {
await f1(x)
try await f1(y)
await f2(x) { print("Hello") }
try await f2(y) { print("Hello") }
try await f2(x) { throw HomeworkError.dogAteIt }
try await f2(y) { throw HomeworkError.dogAteIt }
await f3(x, x)
try await f3(x, y)
}
// Treat @rethrows protocols that inherit AsyncSequence like they are
// AsyncSequence for the purpose of rethrowing methods.
@rethrows
protocol InheritsAsyncSequence: AsyncSequence { }
extension InheritsAsyncSequence {
func blah() async rethrows -> [Element] {
try await self.reduce(into: [Element]()) { $0.append($1) }
}
}
// Ensure that we can get the thrown error type from next().
struct Data { }
struct ErrorSequence<Element, Failure: Error>: AsyncSequence, AsyncIteratorProtocol {
let throwError : Failure
func makeAsyncIterator() -> ErrorSequence<Element, Failure> {
self
}
mutating func next() async throws(Failure) -> Element? {
throw throwError
}
}
enum MyError: Error {
case foo
}
func getASequence() -> any AsyncSequence<Data, MyError> {
return ErrorSequence<Data, _>(throwError: MyError.foo) // ERROR: Cannot convert return expression of type 'any Error' to return type 'MyError'
}
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